Windows VMs will not boot after host Standby

Description

If my host (Windows XP) has most recently come out of standby, then Windows (2000 and XP) guests will not complete boot.
(I get the 'Loading Windows 2000' message and the text progress bar, then freeze, or 'Please wait' in place of the 'Loading Windows 2000' message.)

If my host has most recently been clean booted, or come out of hibernation, then Windows guests will boot properly.